Wind shear
is encoded with the contraction WS followed by a three-digit height, slant character, and winds at the height indicated in the same format as surface winds. The wind shear element is omitted if not expected to occur.
What does WS mean on a METAR?
VRB VIS – Variable Visibility. VV – Vertical Visibility, indefinite ceiling. WS –
Wind shear
. WSHFT – Wind shift.
How often are TAFs issued?
TAFs are prepared
four times a day
and are issued at 2340, 0540, 1140, and 1740 UTC.
How do I read a TAF weather report?
The date and time are formatted using two sets of four digits each with the first two digits representing the day of the month and the second two the 24-hour time in hours only (no minutes since TAFS are issued on the hour). The first set of digits is the start date/time and the second is the end date/time.
What are Metars and TAFs?
METAR is
the international standard code format for hourly surface weather observations
which is analogous to the SA coding currently used in the US. The acronym roughly translates from French as Aviation Routine Weather Report. … TAF is the international standard code format for terminal forecasts issued for airports.
What is the 8 * * * * Group on a METAR?
Runway State Group (RSG)
An 8-figure group which may be added to METAR from civil aerodromes.
What does 9999 mean in a TAF?
9999. This value represents
a visibility greater than 9000
.
meters (7 SM or more)
. The contraction CAVOK (ceiling and visibility OK) may be used when there is no significant weather, the visibility is 10 km or greater, and the ceilings are greater than 5,000 ft.
How long is a TAF valid?
Routine TAFs are valid for
a 24-hour period
and issued four times daily: 00Z, 06Z, 12Z, and 18Z, and are amended (updated) as conditions require.
What distance does a TAF cover?
A TAF is a report valid for
5 statute mile radius
around an airport. A TAF’s terminal area then extends out an additional 5 statute miles, so 10 statute miles total.
How long is an Airmet valid for?
AIRMETs are routinely issued for
6 hour periods
beginning at 0245 UTC. AIRMETS are also amended as necessary due to changing weather conditions or issuance cancellation of a SIGMET.
What does prob mean in TAF?
“PROB:”
Probability forecasts
The time group is the same as the “BECMG” time groups. The numbers indicate the first two numbers of the hour. So 0123/0201 means from the 1st at 2300Z to the 2nd at 0100Z. You won’t ever see a day of the month in PROB and BECMG forecast time groups.
What does 5SM tell you on a TAF report?
(5SM)
The expected prevailing visibility is forecast in statute miles and fractions of statute miles followed by SM to note the units of measure
. Statute miles followed by fractions of statute miles are separated with a space, for example, 1 1/2SM.
What does Qnh mean on a TAF?
QNH. The QNH is the atmospheric pressure corrected to
mean sea level
(based on International Standard Atmosphere conditions throughout the height difference) and is reported in the METAR rounded down to the nearest whole hectopascal. Some aerodromes report the QNH pressure in the METAR in inches of mercury.
Is TAF AGL or ASL?
Heights in METAR
and TAF are always stated as height AGL
. On the other hand, heights in graphic area forecasts (GFA) and PIREPs are normally stated as height ASL, since terrain heights are variable over the larger area covered.
What is the validity of METAR and TAF?
A TAF report is
valid for 24 to 30-hour time periods
and is typically updated four times a day. Thus, the distinction is quite clear – a METAR pertains to current weather conditions, while a TAF pertains forecasted weather for the next 24 to 30 hours.
WHO issues SIGMETs?
NWS
has four Meteorological Watch Offices which issue SIGMETs: the National Centers for Environmental Prediction Aviation Weather Cen- ter (AWC), Alaskan Aviation Weather Unit (AAWU), the Honolulu Forecast Office and the Guam Forecast Office.
